1. Field of the Invention
The present invention relates to a socket for a semiconductor device, the socket being used to connect external leads of a surface-mounting semiconductor device to an external circuit for testing, etc.
2. Description of the Related Art
FIG. 9 is a sectional side elevation view of a conventional socket for a semiconductor device disclosed in, for example, Japanese Examined Utility Model Publication No. 4-14877. In FIG. 9, external leads 3 extend outwardly from every side of a package 2 of the surface-mounting semiconductor device 1. Contacts 11 of the socket 10 for the semiconductor device, having a springing property are disposed at positions corresponding to each of the external leads 3 of the semiconductor device 1.
In this socket 10, positioning and supporting of the semiconductor device 1 are performed by placing the contacts 11 on the bottom side of the external leads 3 and on the side faces of the package 2. Electrical connection is achieved by urging a member such as a holding cover, which is shown by a broken line, toward the upper portion of the external leads 3, opposite to the portion where the contacts 11, having a springing property, have been placed.
FIG. 10 is a sectional side elevation view of another conventional socket for a semiconductor device disclosed in, for example, Japanese Unexamined Patent Publication No. 8-227772. Members that are common with or equivalent to those of FIG. 9 are designated using like reference characters. A movable cover 13 moves up and down above a body 12 of the socket 10, and movable contact terminals 14, having a springing property, are disposed in the body 12 at positions corresponding to the external leads 3, and a positioning base 15 is also disposed in the body 12 to position the semiconductor device 1.
In this socket 10, positioning as well as supporting of the semiconductor device 1 is performed by placing the positioning base 15 underneath the root portion of the external leads 3, sliding the positioning base 15, which is a thin and tall square frame as viewed from above being, disposed in the body 12, from a side of the package 2 of the semiconductor device 1. At a pressed-down position of the movable cover 13, the semiconductor device 1 is set into the socket 10 (the movable contact terminals 14 are relieved from the top surface of the external leads 3 by a downward motion of the movable cover 13), and then, when the force applied to the movable cover 13 is relieved, it moves upwardly by its spring force so that the movable contact terminals 14 are placed on the top surface of the external leads 3 opposite to the portion attached to the frame of the positioning base 15 by a spring force of the movable contact terminals 14. This results in electrical connection between the external leads 3 and the movable contact terminals 14.
In any of the conventional sockets for a semiconductor device formed as above, positioning is performed by adapting the outer surfaces of the package of the semiconductor device. Then, the problem lies in the necessity to prepare each socket for each semiconductor device from each manufacturer, because there is no commonality of size packages from each manufacturer, even if the number and positions of leads are the same. That is, although there is commonality of the tip end positions of the leads, which is important when mounting the semiconductor on a printed board, the dimensions of the outside shape of the package are different for each manufacturer. Therefore, a specific socket for each semiconductor device from each manufacturer has been necessary.
In addition, in any of the conventional sockets for a semiconductor device, the contacts or the movable contact terminals for electrical connection to the external leads, have been designed as a single unit with the portion to be mounted on the printed board for testing, the spring portion and the top or bottom side of the external leads, linking together. This causes the length of the contacts or the movable contact terminals to be longer and the outer shape of the socket to be larger. Therefore, there has been a problem that these sockets are not suitable for the transmission of high-speed signals because of the long length of the electrical path.